First, as I recall the movement in the Marine Chronograph is in fact based on the Laemania movement.

So, market presence (in this case, relative pricing), is generally a reflection of supply and demand. I would suggest that AP is so well known for sporty chronographs that it creates a demand. PP is PP ('nuff said), and VC has created a demand for it's sportier watches.

When I think Breguet, I think elegance. Generally dressy watches, with amazingly elegant movements. Sportier watches are probably not as key to their business as they are with the other lines you mention. Hence, lesser demand...

That's pretty much pure philosophy, with no hard data, but it's probably not far from the truth. Which means, if you like the Breguet, you can get a great deal on an amazing watch. I'd choose to enjoy that...